The invention relates to a medical instrument, in particular resectoscope comprising a first work element for treating body tissue, which can be connected via an elongate work element holder to a handle at a proximal end for moving the work element, the handle having a movable carriage which has a first seat for releasable attachment of the work element holder to the carriage, and comprising a receiver for an endoscope whose endoscope shaft, in the assembled state, extends substantially parallel to the first work element holder.
A medical instrument of the abovementioned type is used in minimally invasive surgery, particularly in the field of urology. In urology, such an instrument is used to dissect tissue, in particular to cut tissue, in the urethra for example. Such an instrument is also known as a resectoscope, although the present invention is not limited to a resectoscope. The instrument is usually combined with an endoscope.
An instrument known from the document DE-A-103 45 111 has, as its work element, an electrode which is mounted on an electrode holder, which acts as work element holder, at the distal end. The electrode itself is, for example, in the form of a resection loop. With such an electrode, for example in the form of a resection loop, tissue is cut with a tractive action under the effect of high-frequency current applied to the electrode. However, under the effect of high-frequency current, such an electrode can work not only with a cutting action but also, if suitably configured, with a coagulating or vaporizing action. The stated document describes how, instead of using work elements that can be acted on by high-frequency current, it is also possible to use instruments that operate without current, for example blades, curettes, etc.
In the known instrument, the proximal end is provided with a handle which has a carriage comprising a seat for receiving the proximal end of the work element holder. In the case where the work element holder supports an electrode at the distal end, the proximal end of the work element holder on the carriage additionally has a electrical contact arrangement, that is to say, in the assembled state, is electrically conductively connected to the terminal for a power supply cable.
In instruments of this kind, it is customary to provide a plurality of different work elements, each with their respective work element holder, which are interchanged by the physician as and when desired and can be secured in the seat of the carriage. Depending on the preference of the physician using the instrument, it is sometimes preferred to cut tissue with an electrode, that is to say using high-frequency current, or to cut it in a purely mechanical way without current, for example with a blade. If, for example, a blade that operates without current is to be used instead of the electrode for cutting tissue, the electrode and its work element holder (electrode holder) in the known instrument are released from the carriage and then removed, and the blade with its work element holder is secured in the same seat on the carriage. This means that all the different work elements available, and the work element holders connected to them, are always secured at the same site on the carriage. Thus, the position of the work element at the distal end of the work element holder, which position is determined by the shape of the work element and of the work element holder, is at all times fixed, in particular the position of the work element relative to the distal viewing window of the endoscope and, therefore, relative to the viewing field of the endoscope. Therefore, if it is desired to be able to use the same work element, for example a blade or a resection loop, in different spatial positions, in particular with respect to the viewing field of the endoscope, it is necessary, in the known instrument, to store the same type of work element, for example a resection loop, in a plurality of different geometric configurations of the work element and of the work element holder. This, however, increases the cost of such an instrument.
The document DE-A-42 42 143 discloses a high-frequency, multi-functional hand-held surgical instrument for bipolar coagulation and cutting and also for irrigation of the operating site and suctioning of fluid and tissue sections in endoscopic interventions, said instrument being able to be connected to a high-frequency generator and to irrigation and suction means. In this known instrument, a high-frequency coagulation probe with two coagulation electrodes, and a high-frequency cutting probe with a cutting needle or cutting loop and with an insulated counter-electrode, can be secured at the same time on the instrument. The two high-frequency probes are each assigned a slide on the handle of the instrument, so that the two probes can be alternately and individually moved in the axial direction, in order to carry out a treatment procedure. The document does not disclose how the two probes are secured on the slides.